When you press Start / Search to search for files and folders, you can press More advanced Options to select:

Search System folders
Search hidden files and folders
Search subfolders
Case sensitive
Search tape backup

You can make default selections via the registry:

1. Use the Registry Editor to navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer.

2. The following Value Names correspond to the GUI and are all REG_DWORD data types. A data value of 1 selects the option, and a data value of 0 de-selects it:

SearchSystemDirs
SearchHidden
IncludeSubFolders
CaseSensitive
SearchSlowFiles

NOTE: You must logoff / logon for these settings to take effect.